Visiting your town!

I think for a zen theme, a pattern like this would look really great:
http://acnlpaths.tumblr.com/post/116315825052/kitsune-gari-as-promised-ive-uploaded-the-qr
I think some flowers would look lovely around your dreamie's houses. For me the best zen feeling flowers would be lilies and violets. They both have a very natural feeling to them.
One thing that stood out to me is I think you should move where you zen garden is. I think it would look more scenic if it was further away from your path. You could decorate around it with other PWPs nearby like a zen clock, zen streetlight, or zen bell. I think cut off bamboo would look lovely around the zen garden as well. You have a lot of space where you could put this new zen garden area, I'd suggest just pushing it back, maybe the area where Rowan's house is once he moves out.
Also, I think leaving your cobblestone without patterns on them would look best for a zen theme. Like, not putting a pattern on top of the area around Retail, Tree Plaza, etc. would look nice and natural with your theme.
Continuing on, I think an area to sit next to the cafe would look nice, like a metal bench for instance. I think that would look good with your zen theme.
I agree that the illuminated items should go, since they may contrast with the zen theme. Instead, I would suggest a wisteria trellis or flower arch. Since you said you want your town to be forest themed as well, I think these PWPs would look good.
I like your placement of the fence PWP, since you said you were going for a forest theme, I think it matches that well. To continue with that theme, I'd suggest putting a log bench somewhere in front of it with perhaps a zen streetlight nearby as well.
You have a lot of space to the right of your town hall, so I think this area has a lot of potential to be a nice PWP area. I don't think the solar panel would match with your theme, but I like your placement of Resetti. In this area, I think you could have a zen bell and zen bench with cut off bamboo around.
You have a good amount of space around your campsite as well, and the placement of the campsite is very good. I'd suggest a well and log bench area nearby.
I think the yellow bench looks good with Chief's house, but I think you have a good space to the right to decorate it further. Perhaps a windmill or wind turbine would look nice, especially with the waterfall there.
I really like the location of all of your houses. I think in the path up to Tamsyn's house, a wisteria trellis would look nice.
A bus stop PWP would fit well with your town theme. I'd suggest putting one somewhere near the train station, either to the left of it or along the path leading up to it.
I think bushes along your paths would look great as well.
Hopefully this advice helped, and best of luck on continuing your town!